President Bush had pledged to veto any bill that merely extended the temporary law without resolving the matter of immunity for telecommunications firms that helped the government with its secret eavesdropping program after 9/11. A "patchwork extension" wouldn't give the security needed to protect the nation, Mr. Bush said, and he urged Republican lawmakers to vote against it.

House Democratic leaders said they would not be "jammed" by the White House into accepting the Senate version of the bill – which includes the immunity provision – and wanted more time to work out differences with the Senate.

As a result, at the stroke of midnight Saturday, the Protect America Act expired. The risk to national security is not yet clear, but the political firefights on both sides of the aisle couldn't be missed.

Bush said Thursday that failure to update the Protect America Act will "harm our ability to monitor new terrorist activities and could reopen dangerous gaps in our intelligence."